Natamycin, also known as pimaricin, was first isolated in 1955 from the fermentation broth of a culture of Streptomyces natalensis obtained from soil taken near the town of Pietermaritzburg In Natal, South Africa. (A. P. Struyk et al, Antibiotics Annual, 878 (1957-1958)). Pimaricin, designated natamycin by the WHO, is produced either from Streptomyces natalensis or Streptomyces gilvosporeus.
Early patents describe recovery processes requiring multiple purification steps and involving relatively expensive unit operations. British patent GB 846,933 discloses an adsorption/elution recovery of natamycin from fermentation broth using water miscible polar solvents such as methanol, butanol and acetone. U.S. Pat. No. 3,892,850 discloses recovery from fermentation broth by extraction into an organic solvent having limited water miscibility, followed by recovery from the solvent. U.S. Pat. No. 3,378,441 claims recovery of natamycin by salting it out of fermentation broth followed by solvent dissolution and evaporative precipitation. A later patent, GB 2,106,498, describes vacuum concentration or butanol extraction of filtered fermentation broth to obtain a raw antifungal complex from which natamycin can be isolated. WO 92/10580 discloses solubilization of natamycin with methanol at low pH, followed by removal of broth solids. Under these conditions, natamycin is susceptible to acid degradation, with potential for depressed recovery yield and reduced product purity. Thus, the prior art does not teach an efficient method for recovery of high quality natamycin.